Note:
A simple "spellchecking" program is included in this distribution.
It is a perl program named "spellcheck". It simply prints the
analysis of the input text; it provides no way to modify the text.
It is simply given as a demonstration of the module. Type
spellcheck -h
for a usage summary. If no input files are specified, it will
read from stdin. After each line of input, it will print the
analysis of the terms. By default, it only gives output for
terms which are "incorrect". Give it the -v option to have it
report on the "correct" terms as well.
Tests:
'make test' currently does nothing. To test the installation,
try out the "spellcheck" program provided.
NAME
Text::Ispell.pm - a class encapsulating access to the Ispell
program.
SYNOPSIS
# Brief:
use Text::Ispell;
Text::Ispell::spellcheck( $string );
# or
use Text::Ispell qw( spellcheck ); # import the function
spellcheck( $string );
# Useful:
use Text::Ispell qw( spellcheck );
for my $r ( spellcheck( "hello hacking perl shrdlu 42" ) ) {
print "$r->{'type'}: $r->{'term'}\n";
}
DESCRIPTION
Text::Ispell::spellcheck() takes one argument. It must be a
string, and it should contain only printable characters. One
allowable exception is a terminal newline, which will be chomped
off anyway. The line is fed to a coprocess running ispell for
analysis. The line is parsed on non-wordchars into a sequence of
terms. By default, the set of wordchars is defined in ispell as
letters, digits, and the apostrophe. In other words, the line is
subjected the equivalent of
split /[^a-zA-Z0-9']+/
(ispell has a means to add characters to the default set, but
currently Text::Ispell does not provide access to that feature.)
The result of ispell's analysis of each term is a categorization
of the term into one of six types: ok, root, miss, none,
compound, and guess. Some of these carry additional information.
Text::Ispell::spellcheck returns a list of objects, each
corresponding to a term in the spellchecked string. Each object
is a hash (hash-ref) with at least two entries: 'term' and
'type'. The former contains the term ispell is reporting on, and
the latter is ispell's determination of that term's type (see
above). For types 'ok' and 'none', that is all the information
there is. For the type 'root', an additional hash entry is
present: 'root'. Its value is the word which ispell identified
in the dictionary as being the likely root of the current term.
For the type 'miss', an additional hash entry is present:
'misses'. Its value is a string of words, comma-separated, which
ispell identified as being "near-misses" of the current term,
when scanning the dictionary.
A quickie example:
use Text::Ispell qw( spellcheck );
for my $r ( spellcheck( "hello hacking perl shrdlu 42" ) ) {
if ( $r->{'type'} eq 'ok' ) {
# as in the case of 'hello'
print "'$r->{'term'}' was found in the dictionary.\n";
}
elsif ( $r->{'type'} eq 'root' ) {
# as in the case of 'hacking'
print "'$r->{'term'}' can be formed from root '$r->{'root'}'\n";
}
elsif ( $r->{'type'} eq 'miss' ) {
# as in the case of 'perl'
print "'$r->{'term'}' was not found in the dictionary;\n";
print "Near misses: $r->{'misses'}\n";
}
elsif ( $r->{'type'} eq 'none' ) {
# as in the case of 'shrdlu'
print "No match for term '$r->{'term'}'\n";
}
}
According to the ispell man page, there should be two more
types: compound and guess. However, I have not figured out how
to elicit responses of these types from ispell.
ERRORS
`Text::Ispell::spellcheck()' starts the ispell coprocess if the
coprocess seems not to exist. Ordinarily this is simply the
first time it's called.
ispell is spawned via the `Open2::open2()' function, which
throws an exception (i.e. dies) if the spawn fails. The caller
should be prepared to catch this exception -- unless, of course,
the default behavior of die is acceptable.
Nota Bene
The full location of the ispell executable is stored in the
variable `$Text::Ispell::path'. The default value is
/usr/local/bin/ispell. If your ispell executable has some name
other than this, then you must set `$Text::Ispell::path'
accordingly before you call `Text::Ispell::spellcheck()' for the
first time.
AUX FUNCTIONS
add_word(word)
Adds a word to the dictionary. Be careful of capitalization. If
you want the word to be added "case-insensitively", you should
call `add_word_lc()'
add_word_lc(word)
Adds a word to the dictionary, in lower-case form. This allows
ispell to match it in a case-insensitive manner.
accept_word(word)
Similar to adding a word to the dictionary, in that it causes
ispell to accept the word as valid, but it does not actually add
it to the dictionary. Presumably the effects of this only last
for the current ispell session.
parse_according_to(formatter)
Causes ispell to parse subsequent input lines according to the
specified formatter. As of ispell v. 3.1.20, only 'tex' and
'nroff' are supported.
set_params_by_language(language)
Causes ispell to set its internal operational parameters
according to the given language. Legal arguments to this
function, and its effects, are currently unknown by the author
of Text::Ispell.
save_dictionary()
Causes ispell to save the current state of the dictionary to its
disk file. Presumably ispell would ordinarily only do this upon
exit.
terse_mode()
nonterse_mode()
In terse mode, ispell will not produce reports for "correct"
words. This means that the calling program will not receive
results of the types 'ok', 'root', and 'compound'.
ispell starts up in NON-terse mode, i.e. reports are produced
for all terms, not just "incorrect" ones.
LIMITATIONS
Currently this package assumes, and only supports, the default
language, i.e. English. It does not provide access to the
features of ispell which allow the selection of alternate
languages or dictionaries.
FUTURE ENHANCEMENTS
Take advantage of these ispell options:
-d file
Specify an alternate dictionary file.
For example, use -d deutsch to choose a German dictionary.
-p file
Specify an alternate personal dictionary.
-w chars
Specify additional characters that can be part of a word.
-B Report run-together words with missing blanks as
spelling errors.
-C Consider run-together words as legal compounds.
-P Don't generate extra root/affix combinations.
-m Make possible root/affix combinations that aren't
in the dictionary.
I should consider allowing these kinds of options to be set at
any time; this would entail stopping and restarting the
coprocess.
DEPENDENCIES
Text::Ispell uses the external program ispell, which is the
"International Ispell", available at
http://fmg-www.cs.ucla.edu/geoff/ispell.html
as well as various archives and mirrors, such as
ftp://ftp.math.orst.edu/pub/ispell-3.1/
This is a very popular program, and may already be installed on
your system.
Text::Ispell also uses the standard perl modules FileHandle,
IPC::Open2, and Carp.
AUTHOR
jdporter@min.net (John Porter)
This module is free software; you may redistribute it and/or
modify it under the same terms as Perl itself.